The technology disclosed herein generally relates to methods and apparatus for detecting and classifying repetitive signals.
A receiver system is any system configured to receive energy waves and process these energy waves to identify desired information carried in the energy waves. As used herein, an “energy wave” is a disturbance that propagates through at least one medium while carrying energy. For examples, energy waves may comprise electromagnetic waves, radio waves, microwaves, sound waves or ultrasound waves.
Typically, a receiver system includes a transducer and a receiver. A transducer may be any device configured to convert one type of energy into another type of energy. The transducers used in a receiver system are typically configured to receive energy waves and convert these energy waves into an electrical signal. An antenna is one example of a transducer. A receiver processes the electrical signal generated by a transducer to obtain desired information from the electrical signal. The desired information includes information about signals carried in the energy waves.
Oftentimes, energy waves are used to carry repetitive signals. A repetitive signal is a signal that has a time period over which some aspect of the signal repeats. Repetitive signals are used in timing operations, synchronization operations, radar operations, sonar operations, and other suitable operations. For example, the characteristics of a repetitive signal may be used to synchronize two or more devices. The characteristics of a repetitive signal can be described through a process known as signal descriptor word (SDW) generation that feeds the output from a wideband receiver.
Signal processing systems with fixed processing resources must adjust their processing to changing signal conditions. In particular, a SDW generator in a wideband receiver may receive many signals of different types, such as radar, navigation, communication, etc. These signals vary widely in bandwidth and hence they must be processed at rates commensurate with those bandwidths. Also, these signals collectively change over time from moment to moment as new ones enter and old ones leave. In addition, the receiver must describe each signal properly and with very low latency. Latency is extremely important in these contexts since there can be far too many signal samples to store for later processing and there can be very strict requirements on responding to certain of the signals as soon as they are detected. Also, this must be done on fixed hardware with fixed processing resources such as those within an application-specific integrated circuit (ASIC) or a field-programmable gated array (FPGA).
Previous solutions to process such widely various and varying signals involve running each channel or data stream at the full sample rate. While this is easy to design, such inefficient full-bandwidth processing is wasteful of computing resources, especially when used in FPGA and ASIC implementations. Accordingly, it would be desirable to provide enhanced systems and methods for processing widely various and varying signals on fixed hardware with low latency for all signals.